Portsdown 4 Wikki, EasyCap and more

Discussion about this major DATV Project. See https://wiki.batc.org.uk/The_Portsdown_Transmitter
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G1BVI
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Joined: Wed Aug 02, 2017 7:32 am

Portsdown 4 Wikki, EasyCap and more

Post by G1BVI » Fri Nov 27, 2020 4:05 pm

Its nearly the Xmas break and time to finish my Portsdown 4.(P4)
It will use a Lime Mini.

The Wikki pages for the other versions of the Portsdown all contain block diagrams.
Is there one for the P4?

It also suggests using the Pluto.

My build is going to be a fixed frequency (2.4G) so I assume the Lime is adequate on Oscar 100?

I need an Easy Capas shown on wikki page:-

https://wiki.batc.org.uk/File:Shop1.JPG

but its currently out of stock in the shop.

Any idea when it might be restocked or is this not needed for the P4?

Thanks in advance
73

Nick
G1BVI

G8GKQ
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Re: Portsdown 4 Wikki, EasyCap and more

Post by G8GKQ » Fri Nov 27, 2020 8:36 pm

Hi Nick

Keeping up with the documentation requiremenmts is a constant battle. The nearest that I have come to drawing a Portsdown 4 block diagram is the one below. In addition, all the switch modules and the attenuator recommended for the Portsdown 2020 can be used. For QO-100 you should not need the switches, but I would recommend the attenuator.

A Lime works perfectly well for QO-100.

Whether you need an EasyCap depends on what you are going to use as your camera source. The alternatives to an EasyCap are a Raspberry Pi Camera or a C920 WebCam.

We have been unable to get the correct version of the EasyCap from China at a reasonable price (the lowest quote was for 1000 units), so it will be out of stock for the forseeable future. I am working on getting a cheaper version of the EasyCap integrated in the Portsdown 4, but it is not proving to be easy.

Dave, G8GKQ
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G1BVI
Posts: 300
Joined: Wed Aug 02, 2017 7:32 am

Re: Portsdown 4 Wikki, EasyCap and more

Post by G1BVI » Fri Nov 27, 2020 10:23 pm

Thanks Dave
I have both the logitec and the pi camera installed.

I gather that the GPIO pins are different so the original GPIO breakout board might now be redundant.

Looks like I have all the bits then, just looking forward to a break so I can put it all together.
I did search on the forum under Easy Cap and then Easycap after posting and found the post think it was from July.

Roll on the Xmas break.

Keep safe

73

Nick

G8GKQ
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Re: Portsdown 4 Wikki, EasyCap and more

Post by G8GKQ » Sat Nov 28, 2020 11:25 pm

Hi Nick

There are 2 GPIO pins that have changed for the RPi 4. One drives the ADF4351 (was on 27, now pin 33) which you will not be using, the other is the Band LSB (or D0) this has moved from pin 28 to pin 32.

Pin 32 is available on the GPIO breakout board as the "I" pin which is pin 2 on J03. More details here: https://wiki.batc.org.uk/images/2/27/PO ... CE_SCH.pdf

Dave

g8gtz
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Re: Portsdown 4 Wikki, EasyCap and more

Post by g8gtz » Sun Nov 29, 2020 8:39 am


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